Mounting system for use in mounting a gas turbine engine

ABSTRACT

A mounting system for use in mounting a gas turbine engine having an engine core to an aircraft comprises an engine support arrangement and front and rear mounting assemblies to mount the engine support arrangement to a casing surrounding the engine core. Each of the front and rear mounting assemblies comprises a plurality of circumferentially spaced mounting members to effect the aforesaid mounting of the engine support arrangement to the casing.

This invention relates to mounting systems for use in mounting gas turbine engines on to the fuselages of aircraft.

The mounting of gas turbine engines above the fuselage of an aircraft has advantages with respect to noise. However, there may be some issues concerning rotor failures that need to be addressed.

According to one aspect of this invention, there is provided a mounting system for use in mounting a gas turbine engine having an engine core to an aircraft, the mounting system comprising: an engine support arrangement; front and rear mounting assemblies to mount the engine support arrangement to a casing surrounding the engine core; wherein each of the front and rear mounting assemblies comprises a plurality of circumferentially spaced mounting members to effect the aforesaid mounting of the engine support arrangement to the casing.

The mounting members may be spaced by a distance such that a broken portion of a disc in an engine core cannot strike more than one of the mounting members. Preferably, the mounting members are spaced by a distance such that a broken portion consisting of a third of a disc of a gas turbine engine cannot strike more than one of the mounting members.

Each of the front and rear mounting assemblies may comprise at least two circumferentially spaced mounting members. Conveniently, each of the front and rear mounting assemblies comprises three of the aforesaid circumferentially spaced mounting members.

One embodiment of the invention is suitable for use with gas turbine engines having a fan to provide the flow of air bypassing the engine core. The casing of the engine may define a bypass duct to provide a conduit for the passage of air driven by the fan. The casing may be constructed to provide support for the engine to allow the engine to be mounted on the aircraft.

The mounting system may comprise a plurality of connecting arrangements to connect the engine support arrangement to a carrier to carry the engine. The carrier may comprise a main pylori for attaching the engine to the aircraft.

The connecting arrangement may comprise a plurality of axially spaced connecting members to effect the aforesaid connection of the engine support arrangement to the carrier. The connecting arrangement may comprise at least two axially spaced connecting members. Conveniently, the connecting arrangement comprises three of the aforesaid connecting members axially spaced from one another.

The connecting arrangement may comprise a load spreading element to which the connecting members are attached. The load spreading element may be elongate and may extend across the engine support arrangement. The load spreading element may comprise a brace. The load spreading element may extend axially across the engine support arrangement.

In one embodiment, the engine support arrangement may comprise an arrangement of struts. The struts may be arranged in a warren truss arrangement. In another embodiment, the engine support arrangement may comprise an arrangement of beams that are connected to one another from the front to the rear of the engine support arrangement. In a further embodiment, the engine support arrangement may comprise a generally monolithic structure. The generally monolithic structure may comprise a plurality of substantially parallel beams secured to one another, conveniently by rivets or other suitable securing arrangement. The generally monolithic structure may be part of, or form, an outer casing for the engine.

The casing may be supported on the engine core by a frame arrangement, which may comprise a plurality of A frames. The frame arrangement may be provided towards, or at, the rear of the engine core. The frame arrangement may extend in a single plane generally circumferentially around the core.

The rear mounting assembly may be mounted on the casing in the plane of the frame arrangement. Desirably, at least two of the mounting members of the rear mounting assembly are respectively coincident with two of the A frames.

An embodiment of the invention will now be described by way of example only, with reference to the accompanying drawings, in which:

FIG. 1 is a diagrammatic front view of an aircraft showing the position of the engines;

FIG. 2 is a side view of one of the engines shown in FIG. 2;

FIG. 3 is a rear view of the engine shown in FIG. 2; and

FIG. 4 is a side view showing an impact on a mounting member.

Referring to FIG. 1, there is shown a diagrammatic rear view of an aircraft 10, with the wings and tail removed for clarity. The aircraft 10 comprises a fuselage 12 and two engines 14, 16 connected to the fuselage 12 by pylons 18, 20.

As can be seen, the engines 14, 16 are arranged above the fuselage and extend at an angle of between 30° to 60° to the horizontal. As a result, in the event of failure of one engine, there is a danger that the fragments of the failed component could strike the other engine. For example, as shown in FIG. 1, a fragment 22 of a disc of the engine 14 has broken therefrom and is directed towards the engine 16 as shown by the arrow A. It has been calculated that the failure of a disc causing it to break into a fragment of approximately a one third segment of a disc can cause the worst case ballistic impact.

FIG. 2 shows the engine 16 having an upstream or front region 24 and a downstream or rear region 26. The engine 16 comprises a core 28 shown in broken lines, which is surrounded by a casing 29. The casing 29 defines with the core 28 a bypass duct 30. A fan 32 is provided towards the front 24 of the engine 16 and drives some of the air through the core 28 and the remainder of the air through the bypass duct 30 to provide the propulsive force. It will be appreciated that the structure of the engine 14 corresponds to the structure of the engine 16.

A mounting system 40 is provided on the casing 29 to enable the engine 16 to be attached to the fuselage 12 by the pylori 20 (not shown in FIG. 2).

The mounting system 40 comprises a front mounting assembly 42 and a rear mounting assembly 44. The front mounting assembly 42 is provided in a front mount plane 46, and the rear mounting assembly is provided in a rear mount plane 48. Each of the front and rear mounting assemblies comprises three mounting members 50A, 50B, 50C which are spaced from one another circumferentially around the respective front and rear mounting planes 46, 48.

The mounting system 40 further includes an engine support arrangement 52 in the form of a frame arrangement comprising a plurality of struts 54 in the form of a warren truss arrangement. A load spreading element in the form of an elongate brace 56 extends across the mounting system 40, and can provide the support to the struts 54. Each of the connecting members 50A, 50B, 50C comprises a link 58 (see FIG. 3) which connects the frame arrangement 52 to lugs 60 provided on the casing 29.

The mounting members 50A, 50B, 50C are spaced from each other by a distance which is greater than one third of the circumference of the largest disc. Since the breaking off of one third of a disc is calculated to provide the greatest ballistic impact, by spacing the mounting members 50A, 50B, 50C from one another by a distance greater than this dimension, the impact of the disc cannot occur on more than one of the mounting members. As a result, a fragment of a disc striking the mounting system 40 can, at worse, strike only one of the mounting members 50A, 50B or 50C. In such a case, the load from the engine is 10 is borne by the remaining mounting members.

The brace 56 extending across the frame arrangement 52 includes three axially spaced connecting members 61 which connect the brace 56 and, thereby, the frame arrangement 58 and the engine 16, to the pylori 20 to provide the connection of the engine 16 to the fuselage 12.

Referring particularly to FIG. 3 which shows a rear view of the engine 16, it can be seen that the rear core 28 is connected to the casing 29 by means of a plurality of A frames 62. The A frames 62 extend in substantially the same plane around the casing 29. The rear mount plane 48 can be arranged in the same plane as the A frames 62 and the two outer connecting members 50A can be connected to the casing 29 in the regions of two of the A frames 62. This provides further strength for supporting the engine 16.

Still referring to FIG. 3, the casing 29 is surrounded by hinged cowls 64, which can be opened to allow maintenance on the engine 16. The brace 56 supports the hinges for the cowls 64.

Referring to FIG. 4, there is shown a further drawing of the engine shown in FIG. 2, in which the mounting member 50C in the front mounting plane 56 has been struck by a failed component, such as a fragment of a disc, of the other engine on the aircraft. As a result of the failure of the front mounting member 50C, the frame arrangement 52 transmits the load that was supported by the front mounting member 50C on to the two remaining mounting members 50A, 50B in the front plane 46. The plane arrangement 52 also transferred some of this load to the three mounting members 50A, 50B, 50C in the rear mounting plane 48.

Various modifications can be made without departing from the scope of the invention, for example, the frame arrangement 52 could be replaced by an arrangement of beams riveted together, which may be in the form of a generally monolithic structure, or by any other suitable support arrangement.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon. 

1. A mounting system for use in mounting a gas turbine engine having an engine core to an aircraft, the mounting system comprising; an engine support arrangement; front and rear mounting assemblies to mount the engine support arrangement to a casing surrounding the engine core; characterised in that each of the front and rear mounting assemblies comprises a plurality of circumferentially spaced mounting members to effect the aforesaid mounting of the engine support arrangement to the casing.
 2. A mounting system according to claim 1 wherein the mounting members are spaced by a distance such that a broken portion of a component of an adjacent engine cannot strike more than one of the mounting members.
 3. A mounting system according to claim 1 wherein each of the front and rear mounting assemblies comprises at least two circumferentially spaced mounting members.
 4. A mounting system according to claim 1 wherein each of the front and rear mounting assemblies comprises three circumferentially spaced mounting members.
 5. A mounting system according to claim 1 wherein the casing of the engine defines a bypass duct between the casing and the engine core to provide a path for the flow of air therethrough.
 6. A mounting system according to claim 1 comprising a connecting arrangement to connect the engine support arrangement to a carrier to carry the engine.
 7. A mounting system according to claim 6 wherein the connecting arrangement comprises a plurality of axially placed connecting members to effect the aforesaid connection of the engine support arrangement to the carrier.
 8. A mounting system according to claim 7 wherein the connecting arrangement comprises at least two axially spaced connecting members.
 9. A connecting arrangement according to claim 7 wherein the connecting arrangement comprises three connecting members axially spaced from one another.
 10. A mounting system according to claim 9 wherein the connecting arrangement comprises a load spreading element to which the connecting members are attached.
 11. A mounting system according to claim 10 wherein the load spreading element is elongate and extends across the engine support arrangement.
 12. A mounting system according to claim 10 wherein the load spreading element comprises a brace extending axially across the engine support arrangement.
 13. A mounting system according to claim 1 wherein the engine support arrangement comprises an arrangement of struts.
 14. A mounting system according to claim 13 wherein the struts of the engine support arrangement are arranged in a warren truss arrangement.
 15. A mounting element according to claim 1 wherein the casing is supported on the engine core by a frame arrangement in the form of a plurality of A frames.
 16. A mounting system according to claim 15 wherein the frame arrangement is provided towards or at the rear of the engine core.
 17. A mounting system according to claim 15 wherein the frame arrangement extends in a single plane generally circumferentially around the core.
 18. A mounting system according to any of claim 15 wherein the rear mounting assembly is mounted on the casing in the plane of the frame arrangement.
 19. A mounting system according to claim 18 wherein at least two of the mounting members of the rear mounting assembly are each coincident with a respective one of the A frames.
 20. An engine arrangement comprising a gas turbine engine, a mounting system according to claim 1 and a carrier for connection of the mounting system to the fuselage of an aircraft.
 21. An aircraft incorporating engine arrangement according to claim
 20. 